This invention relates to an air intake device for internal combustion engines with at least one collection manifold and intake tubes branching separately to the individual cylinders of the internal combustion engine, in which the intake tubes extend to the collection manifold and are formed at least partially by a flexible element.
Published German Patent Application No. DE 197 17 272 discloses an air intake apparatus for an internal combustion engine, which has an air collection manifold and individual air channels to the individual cylinders. Adjustable intake tube extensions are associated with the air channels. These air channel extensions comprise setting devices with rocker systems and pantograph-like levers. A disadvantage of this construction lies in the complicated drive mechanism of the intake tube extensions. Especially in internal combustion engines which are used in motor vehicles, there is a danger that these mechanical components may become impaired by environmental influences. Any failure of the mechanisms inevitably leads to a loss of power.
Air intake devices for internal combustion engines are also known which have intake lines made of a flexible tubing. This flexible tubing is contained within a closed system, but a disadvantage of this construction is that the walls of the tubing are ribbed for flexibility, and this needlessly increases resistance to air flow.
It is an object of the invention to provide an air intake system which avoids the aforementioned disadvantages.
Another object of the invention is to provide an air intake device which will have a positive influence on the power of an internal combustion engine with which it is used.
A further object of the invention is to provide an air intake device which will have a simple and reliable construction.
It is also an object of the invention to provide an air intake device which will not substantially increase resistance to flow.
These and other objects have been achieved in accordance with the present invention by providing an air intake device for an internal combustion engine, said device comprising at least one collection manifold and a plurality of intake tubes which branch separately from the collection manifold to individual cylinders of the internal combustion engine, wherein each of the intake tubes extends to the collection manifold and is formed at least partially by a flexible element, and said intake tubes comprise stiff or variable-length portions, which portions are divided into at least two segments mounted so as to be moveable independently of one another.
A significant advantage of the invention is that the intake tubes comprise different regions or segments, and it is possible to couple and decouple the various segments.
In accordance with one embodiment of the invention, the various segments are journaled on a common pivot center. This eliminates complicated linkages or drive systems. The common center permits the necessary adjusting movements to be carried out in a simple manner.
In another embodiment of the invention the segments are longitudinally displaceable. This is especially practical where the segments consist of short pieces of tubing. Of course, it is also possible to combine longitudinally displaceable segments with rotary segments in order to make optimal use of available space.
In a further embodiment the segments are provided with radial and/or axial gaskets at their coupling points. These gaskets assure optimum coupling and prevent the entry of extraneous air.
Another embodiment of the invention describes the overall structure of an air intake device in which rigid first element is coupled to a rotatable or longitudinally moveable second element, which in turn can be coupled to a rigid third element. The longitudinally movable element is equipped at the coupling points with sections of variable length.
These and other features of preferred embodiments of the invention, in addition to being set forth in the claims, are also disclosed in the specification and/or the drawings, and the individual features each may be implemented in embodiments of the invention either individually or in the form of subcombinations of two or more features and can be applied to other fields of use and may constitute advantageous, separately protectable constructions for which protection is also claimed.